How to trigger the 3D transformation widget with G, R or S
First, delete the existing G/R/S bindings by going to Preferences > Keymap > 3D View > 3D View (Global), and scroll down until you find them. Click the "x" button to remove them.



Next, create the new bindings by right click the widget tools in the side panel toolbar, and select "assign shortcut". Then type the key you want the new shortcut to be for that tool.



Unfortunately, you will need to do this seperately for each mode, such as edit/object/pose modes. And edit mode will need to be done for each object type, edit mode shortcuts for meshes are not the same as for curves or metaballs.

Finally, to make these changes apply to all scenes from now on, bring preferences up again and click "Save Preferences"